The present invention relates to optical storage media, and more particularly to controllers for reading and writing to optical storage media.
Optical read and write media drives are well known in the art. Conventional optical read drives include Compact Disc-Read Only Memory (CD-ROM) drives, which can read CD-based formats, and Digital Video Disc-Read Only Memory (DVD) drives, which can read DVD and CD-based formats. Conventional optical write drives include Compact Disc-Read/Write (CD-R) drives, which can read CD-based formats and read and write to Write Once Media, and; Compact Disc-Rewritable (CD-RW) drives, which can read CD-based formats and read and write to Write Once Media and Rewritable Media. Each of these drives conventionally requires different controllers.
FIGS. 1A and 1B are block diagrams illustrating basic conventional controller architectures for optical drives. FIG. 1A illustrates a basic conventional architecture for CD-ROM and DVD controllers. The controller 100 comprises a host interface 104, a buffer manager 106, a decoder 110, a read servo 112, a read channel 114, power drivers 116, and a microcontroller interface 118. The host interface 104 functions as an interface between a host 102, such as a personal computer, and the rest of the controller 100. When the host 102 sends a command to the controller 100 via the host interface 104 to read data on the disc 120, the command is sent to an external microcontroller (not shown) via the microcontroller interface 118. The host""s command is interpreted and sent back to the controller 100. The read servo 112, using the read channel 114 and power drivers 116, finds and collects the data from the disc 120 according to the command. The data is decoded by the decoder 110 and stored in an external Dynamic Random Access Memory 108 (DRAM). The buffer manager 106 manages data flow in and out of the external DRAM 108 via a bus 122. Typically, the bus is either a 16-bit or 32-bit bus. Once enough of the data is decoded and stored in the DRAM 108, the host 102 is notified. The host 102 then collects the data from the external DRAM 108.
FIG. 1B illustrates a basic conventional architecture for CD-R and CD-RW controllers. The controller 150 comprises a host interface 154, a decoder 156, an encoder 158, a read and write servo 160, a buffer manager 162, and a microcontroller interface 164. The host interface 104 functions as an interface between the host 102 and the rest of the controller 100. To perform a write, the host 152 sends a command to the controller 150 via the host interface 154 to write data on the disc 170. The command is sent to an external microcontroller (not shown) via the microcontroller interface 164. The host""s command is interpreted and sent back to the controller 150. The data is encoded by the encoder 158 into the proper format. The data is then physically written onto the disc 170 by the read/write servo 160, using the read channel and power drivers 168, according to the command. How the data is written onto the disc 170 is determined by the write strategies 166. Typically, the write strategies 166 and the read channel/power drivers 168 reside outside of the controller 150. The buffer manager 162 manages data flow in and out of the external DRAM 172 via the bus 174 during the writing of the data. The reading of data with controller 150 functions in the same manner as with the controller 100.
However, if a consumer desires the functionality of all four drives, the consumer must purchase multiple drives. One drive could be manufactured with a combination of the two controllers 100 and 150, but an additional bridge chip is required to multiplex the controllers together. This is very costly to manufacture with no corresponding increase in performance. In fact, a decrease in the speed of the host would be required to interface with the combined controller. This results in a performance penalty for the host.
Accordingly, there exists a need for an integrated controller to process both optical reads and optical writes of multiple optical media. The integrated controller should be cost efficient to manufacture and also avoid a performance penalty for the host. The present invention addresses such a need.
The present invention provides an integrated controller to process both optical reads and optical writes of multiple optical media. The integrated controller includes a host interface; a buffer manager coupled to the host interface; an embedded memory coupled to the buffer manager; an integrated encoding/decoding engine coupled to the buffer manager; a data channel interface coupled to the integrated encoding/decoding engine; and an integrated servo/recording processor coupled to the integrated encoding/decoding engine and the data channel interface, where the integrated servo/recording processor includes a set of write strategies. The present invention provides a controller which integrates the functionality of the conventional controllers into an integrated processor. With the controller in accordance with the present invention, a single drive may be provided which can read CD-based and DVD-based formats, read and write to Write Once Media, and read and write to Rewritable Media. The architecture of the controller is designed such that its manufacture is cost effective and a performance penalty for the host does not occur. In addition, the controller may also be used with conventional optical drives. Thus, with the present invention, the same controller may be used for all conventional optical drives as well as with an integrated drive.